Weir construction



Jan. 13, 1970 sfsT EANDER 3,489,287

WEIR CONSTRUCTION 3 Sheets-Sheet 1 Filed Nov. 19, 1968 mvmon PHILIP B. STREANDER C. (1. W w ATTORNEYS Jan. 13, 1970 PQ B. STREANDER WEIR CONSTRUCTION Filed Nov. 19, 1968 3 Sheets-Sheet 2 ATTORNEYS PHILIP B. STREANDER sm nux wmw as Mm Ii IKI II Jan. 13, 1970 'P; B. ST'REANDER 3,439,287

' WEIR CONSTRUCTION Fil ed Nov; 19, 1968 5 Sheets-Sheet 5 .3 o 4 zZj h 10., 3 i

United States Patent 3,489,287 WEIR CONSTRUCTION Philip B. Streander, Treasure Island, Fla., assignor to FMC Corporation, San Jose, Calif., a corporation of Delaware Filed Nov. 19, 1968, Ser. No. 776,868 Int. Cl. B01d 43/00 US. Cl. 210525 20 Claims ABSTRACT OF THE DISCLOSURE A settling apparatus is provided with weir construction permitting adjustment of the position of the skim point to coincide with the clarity zone. The weir construction includes a plurality of elongated weir channels which extend laterally of the direction of flow in the tank and which are spaced along the flow path. Valve means are provided to selectively place individual weir channels into operation.

BACKGROUND OF THE INVENTION Field of invention The present invention relates to weirs and particularly to weirs for skimming relatively clear water 01f of the top of settling tanks.

Description of the prior art In settling tanks, the clarity zone is often variable in size and position. Further, in some cases, the clearest water is obtained near the tank inlet. Conventionally, weirs in settling tanks have been designed and located to accommodate average conditions and therefore when the position of size of the clarity zone varies, the clarity of the efiluent may be seriously affected.

SUMMARY OF THE INVENTION The foregoing problems are solved by the present invention which provides a weir construction for settling tanks facilitating rapid adjustment of the weirs to optimize their operation and permit skimming at the most advantageous position in the tank.

Broadly, the apparatus provided by this invention comprises a liquid receiving tank having an inlet. A plurality of elongated, liquid receiving weir defining structures are disposed within the tank. The structures are spaced along and disposed transversely to an imaginary line extending from the inlet across the tank and each structure includes an outlet. An effluent conduit is provided as are gate means located between the outlets and the conduit. The gate means is operable to throttle and selectively block and unblock individual outlets to adjust the horizontal distance from the inlet to an operating structure as well as the flow rate in individual structures. Thus, the apparatus may be adjusted to skim water off the tank at any preselected position.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a top plan view of settling apparatus which includes a weir construction embodying the concepts and principles of the instant invention;

FIGURE 2 is a cross-sectional view taken substantially along line 22 of FIG. 1;

FIGURE 3 is an enlarged cross-sectional View taken substantially along line 33 of FIG. 1; and

FIGURE 4 is an enlarged cross-sectional view taken substantially along line 4-4 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT A settling apparatus which embodies the concepts and principles of the instant invention is illustrated in the 3,489,287 Patented Jan. 13, 1970 drawings and is broadly designated by the numeral 10. Apparatus 10 is useful for clarifying liquids in general. That is to say, apparatus 10 may be utilized for separating liquids from solid material. In this regard, apparatus 10 is particularly adapted for use in conjunction with a sewage disposal plant in conducting the final settling operations on activated sludge.

Apparatus 10 comprises a liquid receiving tank 12. Tank 12 is of a significant size as will be appreciated by those skilled in the art and is preferably constructed of poured concrete or the like. Also, generally speaking, tanks such as 12 are often installed below grade, as indicated in the drawings.

Tank 12 is generally rectangularly shaped and includes end Walls 14 and 16, side walls 18 and 20 and a bottom Wall 22. Walls 14, 16, 18, 2 0, and 22 are interconnected (and preferably integral) to present a settling zone 24 of substantial size. An inlet 26 for tank 12 is disposed centrally of wall 16 at the upper portion 16a thereof. Wall 16 is also provided with an inclined hip portion 16b disposed just beneath the mouth 26a of inlet 26.

A baflle 28 extends laterally across tank 12 between Walls 18 and 20 and in front of mouth 26a in a position to deflect sludge entering through inlet 26. A slab 30 extends between walls 18 and 20 above baffle 28 and a sump 32 in bottom wall 22 is disposed directly beneath baffle 28. Slab 30 serves to contain material which splashes upwardly upon contact with bafile 28 and sump 32 serves for collecting solids which settle either upon contact with baffle 28 or later during the settling process. In this regard, it is to be noted that wall 22 is sloped downwardly from wall 14 toward sump 32 and a rake apparatus 34 is disposed within tank 12 for moving solid materials along wall 22 and into sump 32. Rake 34 is of conventional construction and plays no part in the instant invention. Similarly, sump pump 36 is of conventional design for removing accumulated sludge from sump 32.

A down turned portion 30a on slab 30 is spaced from upper portion 16a of wall 16 presenting an air vent 38 therebetween. The fluid entering tank 12 passes under vent 38 and through a throat 40 between the lower ex tremity of down turned portion 30aof slab 30 and inclined hip portion 16b of wall 16.

Tank 12 is provided with an effluent conduit 42 which comprises an enclosed collecting ramp 44 extending longitudinally of tank 12 and a chute 46 which extends laterally of tank 12 along wall 14. Ramp 44 includes a lower wall 48 which is inclined downwardly toward wall 14 of tank 12. A pair of side walls 50 and 52 extend upwardly from wall 48 and an end wall 54 closes the end of ramp 44 nearest inlet 26. An upper Wall 56 extends laterally between sidewalls 50 and 52 to close the top of ramp 44.

Chute 46 includes an end wall 58, an outer wall 60 and a bottom wall 61 which is inclined downwardly and outwardly to facilitate gravitational flow. Wall 14 has an upper portion 14a adjacent chute 46 which serves as the inner wall of chute 46.

An elongated trough 62 is disposed atop ramp 44. Trough 62 includes a pair of opposed side walls 64 and 66 which are vertically aligned with walls 50 and 52 respectively of ramp 44. The upper wall 56 of ramp 44 extends beyond the latter toward wall 16 of tank 12 and serves as the bottom wall of trough 62. An end wall 68 extends laterally between walls 64 and 66 and upwardly between wall 56 and slab 30, thus serving to close the end of trough 62 and at the same time provide support for trough 62 as well as ramp 44. In this regard, slab 30, the walls of trough 62 and the walls of ramp 44 are preferably formed .of concrete and are integral as best illustrated in FIG. 2.

A plurality of elongated, transversely U-shaped weir channels 70, 72 and 74 extend laterally across tank 12 between wall 64 of trough 62 and side wall 20 of tank 12. Likewise, another plurality of identical weirs 76, 78, and 80 extend laterally of tank 12 between wall 66 of trough 62 and side wall 18 of tank 12. As best illustrated in FIG. 4, each weir 70, 72, 74, 76, 78 and 80 includes a lower wall 82 and a pair of opposed, spaced, vertically extending side walls 84 which are interconnected by Wall 82. A longitudinally extending wooden blade 86 is preferably provided at the upper extremity of each side wall 84.

Openings 88, 90 and 92 are provided in wall 64 for weirs 70, 72 and 74 respectively. Likewise, openings 94, 96 and 98 are provided in wall 66 for weirs 76, 78 and 80 respectively. Thus, all of the weirs 70, 72, 74, 76, 78 and 80 are in fluid communication with the interior of trough 62. Walls 82 are all inclined downwardly in a direction toward trough 62 to establish a flow direction thereinto.

Walls 64 and 66 are provided with three sets .of opposed, vertically extending notches 100, 102 and 104 which slidably receive respective panels 106, 108 and 110 which extend laterally across trough 62. Thus, trough 62 is divided into three chambers 112, 114 and 116 disposed centrally of tank 12. Chamber 112 and its associated weirs 70 and 76 present and elongated, liquid receiving, weir defining structure 118. Chamber 114 and its associated weirs 72 and 78 present an elongated, liquid receiving, weir defining structure 120. Similarly, chamber 116 and its associated weirs 74 and 80 present an elongated, liquid receiving, weir defining structure 122. Structures 118, 120 and 122 are spaced along and extend transversely to an imaginary line 124 which extends across tank 12 from inlet 26. Manifestly, line 124 is also disposed along the path of flow through tank 12.

Chambers 112, 114 and 116 are provided with respective outlets-126, 128 and 130 through wall 56 which intercommunicate chambers 112, 114 and 116 with the interior of ramp 44. Respective valves 132, 134 and 136 are provided for outlets 126, 128, and 130. Valves 132, 134 and 136 each comprise a plate 138, a shaft 140 pivoted between walls 62 and 64, a linkage 142 connecting plate 138 to shaft 140, and an operating lever 144. Thus, when a lever 144 is actuated, its plate 138 is swung upwardly away from the corresponding outlet 126, 128 or 130.

The blades 76 on the sidewalls 74 of weirs 70, 72, 74, 76, 78 and 80 are preferably disposed at a common level within tank 12. Thus, a liquid level is maintained within tank 12 at the upper edges of blades 76. This liquid level is represented by the dashed line designated by the numeral 146.

In operation, valves 132, 134 and 136 are actuated to open outlets 126, 128 and 130. Thus, all of the weirs 70, 72, 74, 76, 78 and 80 are in fluid communication with outlet chute 46. That is to say, clarified water skims across blades 76, moves downwardly along lower walls 82 and passes through openings 88, 90, 92, 94, 96 and 98 into chambers 112, 114, and 116. From chambers 112, 114, and 116 the clarified water moves through outlets 126, 128 and 130 into enclosed ramp 44 and thence outwardly along chute 46.

Viewing FIG. 1, it can be seen that tank 12 may be divided into three theoretical zones, A, B, and C, the boundaries of which coincide with the positions of panels 106, 108 and 110. If the clarity zone is within zone B, for example, valves 132 and 136 may be actuated to close openings 126 and 130. Panels 106', 108 and 110 are in place, and thus, weirs 70, 74, 76 and 80 are rendered inoperative. On the other hand, weirs 72 and 78 are operative to skim clarified water from zone B. Hence, by manipulation of valves 132, 134 and 136, the distance from inlet 26 to an operative structure 118, 120 or 122 is readily altered.

Panels 106, 108 and may also be manipulated to produce alternate operating results. For example, if the clarity zone coincides with zone C, if valves 132 and 134 are closed and if panels 106 and 108 are in place, panel 110 may be removed to cause water to drain over the end 148 of wall 56 and onto chute 46 to thereby actuate structure 122. Also, for example, structures 118 and may be simultaneously actuated by removing panel 106 and opening either valve 132 or 134.

Valves 132, 134 and 136 may be partially opened into a throttling position to achieve other operating results. Also, the panels 106, 108, and 110 may be raised slightly rather than removed completely.

In any event, valves 132, 134 and 136 and panels 106, 108 and 110 present gate means between outlets 126, 128, and and conduit 42 which is operable to throttle and selective block and unblock the outlets 126, 128 and 130 individually to thereby adjust :the horizontal distance from inlet 26 to an operating structure 118, 120, or 122 and to also adjust the flow rate in each individual structure.

I claim:

1. Settling apparatus comprising;

a liquid receiving tank having an inlet;

an effluent conduit;

a plurality of elongated, liquid receiving, weir defining structures disposed within said tank, said structures being spaced along and disposed transversely to an imaginary line extending from the inlet across the tank, each structure having an outlet, said outlets normally communicating with said conduit; and

gate means operably associated with the structures for controlling the flow therein, said means including valve means disposed to selectively block and unblock individual outlets whereby to adjust the horizontal distance from the inlet to an operating structure.

2. Apparatus as set forth in claim 1 wherein said structures are disposed substantially at a common level.

3. Apparatus as set forth in claim 1 wherein each structure comprises a plurality of substantially parallel weir channels.

4. Apparatus as set forth in claim 1 wherein said valve means includes a valve for each outlet.

5. Apparatus as set forth in claim 1 wherein each structure comprises an elongated channel, said channels being generally U-shaped in transverse cross-sectional configuration, presenting opposed, spaced, vertical side walls and a lower wall interconnecting the side walls.

6. Apparatus as set forth in claim 1 wherein each structure comprises a central chamber and a plurality of elongated parallel weir channels extending horizontally outwardly from said chamber, said channels and said chamber being in fluid communication, said outlet being disposed in said chamber.

7. Apparatus as set forth in claim 6 wherein said valve means includes a lever operated valve mounted in each chamber.

8. Apparatus as set forth in claim 6 wherein each chamber comprises a pair of spaced, opposed, parallel, vertical side Walls and a bottom wall interconnecting the side walls, there being a plurality of said channels extending generally perpendicularly outwardly from each side wall, said outlet being disposed in said bottom wall.

9. Apparatus as set forth in claim 8 wherein the walls of the chambers are disposed in end-to-end alignment, the walls of each chamber being integral with the adjoining Walls of adjacent chambers, said chambers thereby presenting an elongated trough.

10. Apparatus as set forth in claim 9 wherein said conduit includes a. collecting ramp underlying said trough and said outlets.

11. Apparatus as set forth in claim 9 wherein said gate means includes means normally disposed across the trough in fluid blocking relationship between adjacent chambers.

12. Apparatus as set forth in claim 11 wherein said blocking means comprises a panel shiftable in the trough from its normal trough blocking position to a trough clearing position.

13. Apparatus as set forth in claim 11 wherein said valve means includes a lever operated valve mounted in each chamber.

14. Settling apparatus comprising:

an elongated, generally rectangular tank having an inlet at one end thereof;

an effluent conduit in said tank including an enclosed effiuent ramp extending longitudinally of the tank toward the opposite end thereof;

an elongated open trough disposed on top of the ramp and extending longitudinally thereof;

a plurality of weir channels extending laterally outwardly from each side of the trough, said channels being disposed substantially at a common level in the tank and being in fluid communication with said trough;

a plurality of removable panels in the trough, in transverse, fluid blocking relationship thereto, normally presenting a plurality of adjacent chambers, each chamber communicating with at least one weir channel and having an outlet intercommunicating the chamber with the ramp; and

a valve for each outlet.

15. Apparatus as set forth in claim 14, said Weir channels being substantially perpendicular to the trough and generally parallel to one another.

16. Apparatus as set forth in claim 15 wherein each chamber has at least one weir channel extending outwardly from each side thereof in substantially opposed, longitudinally aligned relationship.

effluent conduit.

18. Settling apparatus according to claim 17 including means for varying the rate of flow of liquid from said particular portions of said skimming means.

19. Settling apparatus comprising a liquid-receiving tank; inlet passage and discharge passages for said tank;

liquid skimming means in said tank between said inlet and discharge passages; and control means for selectively separating said skimming means into a plurality of separate liquid-skimming units each of which is in independent flow communication with said inlet and said discharge passages.

20. Settling apparatus according to claim 19 wherein said control means is adjustable to permit flow communication between said independent units.

References Cited UNITED STATES PATENTS 2,428,756 10/1947 Lind 2l0-525 2,509,933 5/1950 Lind 210528 X 2,708,520 5/1955 Dallas 210-525 JAMES L. DECESARE, Primary Examiner US. 01. X.R, 2 F52 

